Journal of Stress Physiology & Biochemistry (Apr 2012)
Impact of exogenous salicylic acid on growth and ornamental characteristics of calendula (Calendula officinalis L.) under salinity stress
Abstract
Application of salicylic acid (SA) as a phytohormone has been increased due to resistance to stresses such as salt stress. Pot experiments were conducted to determine the effect of exogenous salicylic acid application on growth and ornamental characteristics of calendula grown under salt stress and greenhouse conditions. For this purpose a factorial experiment based on completely randomized design was conducted with 3 levels of SA (0 (control), 1, 2 mM) and 3 levels of NaCl (0, 100 and 200 mM) with 4 replications. At flowering stage, SA was applied with spraying two times in two week intervals. NaCl was also applied as drench (200 ml per pot) in two day intervals. The results showed that salinity decreased the growth, Chlorophyll reading values, flower number per plant and flower diameter. However, foliar applications of SA resulted in greater root, shoot and total dry weight, plant height and leaf area of calendula plants under salt stress. The highest chlorophyll reading values was obtained from 2.00 mM SA application in all NaCl treatments. Salinity decreased number of flower per plant and flower diameter as ornamental characteristics; however SA increased them under salinity stress. Plants treated with 1.00 mM SA had the highest flower diameter at 100 and 200 mM of NaCl. Electrolyte leakage increased by salinity, however foliar application of SA significantly reduced electrolyte leakage under salt stress. Based on the present results, foliar application of SA treatments can ameliorate the negative effects of salinity on the growth and ornamental characteristics of calendula plants.
